Prosthetic Alignment & Pressure Terms Seminar and Crossword

If the socket is not flexed forward on the pylon, where is the pressure?

Reduced pressure on patellar ligament (pressure tolerant)

↑ Pressure on distal bone ends / distal pole of patella (pressure sensitive)

If the socket is not flexed forward on the pylon, how is gait affected?

↓ Knee Flexion Moment = Provides more knee stability in Loading Response

In Midstance, the work of the hip extensors is increased, working against the resistance of very limited DF to progress onto the forefoot **You may see TTP Pelvic Retraction & Sound Side Short Step

If the ankle (Foot-Tibia Angle) is in 0º DF without a shoe, where will the pressure be concentrated once a shoe is donned?

Note: The floor-to-tibia angle will cause a DF moment, with a resulting increased knee flexion moment in standing

Pressure on proximal posterior & distal anterior residual limb

+ Increased WB on patellar ligament with decreased pressure on distal bony ends

What is likely wrong with the prosthetic alignment if you see pain & redness at the tibial tubercle?

Excess pressure proximal anterior (distal posterior) = Suggests socket is posterior, or not flexed on pylon, creating a knee extension moment

Can also be caused by a small socket or too many sock ply

What is likely wrong with the prosthetic alignment if you see pain & redness at the anterior distal tibia?

Excess pressure distal anterior (proximal posterior) suggests socket anterior or excessively flexed on the pylon

Results in greater knee flexion moment counteracted by forceful quad activity = Bell Clapping

What are the possible causes of Bell Clapping?

+ Lack of total contact around distal stump

+ Increased quad force due to exercise

+ Walking with faster speed with longer steps (increases knee flexion angle in loading)

+ Running

If you see pain & redness at the anterior distal tibia, what can you as a PT do?

Add a sock, or distal stockinette ( especially if using a silicon interface )

Suggest short step lengths with faster cadence

Mobilize lumbopelvic hip & hip flexors to allow longer prosthetic step

What is likely wrong with the prosthetic alignment if the pt reports pain & soreness at the fibular head? What are other possible patient causes?

Suggests valgus moment due to either outset foot or adducted socket

Patient Causes

- Wide BOS

- Hip ADD hypomobility

- ABD contracture

- Impaired balance

What is likely wrong if you see a callous at the terminal tib-fib end?

Habital excess WB on the terminal bony ends due to...

- Socket is too big

- Stump is too small

- Poor suspension is causing pistoning

- Stump volume lost during day if active use

- Possibly socket not flexed on pylon (more specific to Pain & Redness at Tibial Tubercle)

How could knee buckling during initial contact be caused by glute max weakness?

"Critical for pulling the femur backward & thus extending the knee"

If a patient is buckling during initial contact / loading, what should your PT plan look like?

MET for L2-L4 (Quads) & L4-5 (Glutes)

Sustain forceful isometric for glutes & quads in CKC first against bolster (shortened position) then in standing (lengthened position)

Part-whole gait training with resistance + varied timing

Why do you often see IL pelvic rotation from midstance to heel off?

Typically, momentum and GRF cause a knee extension moment from just before midstance through heel off in normal gait ie. typically glutes and quads don’t contribute

Prosthetic ankles provide limited DF and the socket is tilt anteriorly (knee flexion moment) this knee extension moment is not there = Glutes & quads must be trained to forcefully contract before midstance to enable them to power their body over high vertical point of midstance and against the resistance of limited ankle DF, to progress onto the forefoot

When would you want to recommend a multi-axial articulating ankle?

For uneven ground + allows faster gait via longer step

*Think grandma taking her grandkids for walks in the park case

If a patient has to often go up/down hills and do a lot of stairs, what is the best choice for a foot-ankle prosthetic?

K1 Single-Axis Foot > SACH if hilly entrance / stairs ie. more sagittal plan requirements

K2 Multiaxial even better if you quality

When would you recommend a pelite liner with socks & a SC cuff suspension?

Easier to done than neoprene sleeve, avoids silicone allergy concerns and doesn't require hand dexterity to don